冷間圧延りん青銅板における非熱的応力成分の評価

抄録

When considering the strength required for structural materials, the first requirement is the ability to permanently hold stress under static loads. In order to achieve carbon neutrality, there is a need for lean and extreme design. It is important to evaluate the flow stress by removing the strain rate dependence of the material from the results of uniaxial tensile tests at quasi–static strain rates. In this study, the athermal stress component (stress independent on strain rate) of cold–rolled phosphor bronze sheet for springs (JIS–C5210–H) was evaluated using stress relaxation tests and extrapolation by curve fitting. It was found that about 90％ of the 0.2％ proof stress observed in the uniaxial tensile test at quasi–static strain rate was the athermal stress component. It was also found that the thermal stress component (stress dependent on strain rate) accounted for about 10％ and could not be generally ignored. Therefore, it is suggested that evaluation of the athermal stress component is effective as one of the direct methods to evaluate the static strength of structural materials.